Question

A wheel, 14 cm in diameter, makes 3000 revolution per minute. Find its speed in m/second

Answer 1

Circumference = π * Diameter

C = ( 22 / 7 ) * 14

C = 22 * 2

Circumference = 44 cm

Number of revolutions in 1 minute = 3000

Number of revolutions in 60 seconds = 3000

Number of revolutions in 1 second = 3000 / 60 = 50

We know that the distance covered by wheel in 1 revolution is equal to it's circumference.

Distance covered by wheel in 1 revolution = 44 cm

Distance covered in 50 revolutions = 50 * 44 = 2200 cm

Hence,

Distance covered in 1 second = 2200 cm

Speed = 2200 cm/s = (2200/100)m/s = 22 m/s

Answer 2

diameter=14cm
radius=7cm
circumference=distance covered in 1 revolution= 2 ×22÷7×7
=2×22
=44cm =0.44m
Now,
revolutions in 60 s(1min)=3000
revolutions in 1s. =3000÷60
=50
thus,
distance covered in 50 revolution=50×0.44
=22 m
speed =d÷t
=22m÷1s
=22m/s